Chair of Food Safety, Faculty of Veterinary Medicine, LMU Munich, Schoenleutnerstr. 8, 85764, Oberschleissheim, Germany.
Chair of Food Safety, Faculty of Veterinary Medicine, LMU Munich, Schoenleutnerstr. 8, 85764, Oberschleissheim, Germany.
Food Microbiol. 2019 Dec;84:103275. doi: 10.1016/j.fm.2019.103275. Epub 2019 Jul 18.
The causative agents of zoonotic bovine tuberculosis (bTB), Mycobacterium bovis and M. caprae, are members of the M. tuberculosis complex (MTC). Wildlife such as red deer infected with bTB are often without pathological findings, thus meat thereof may be classified as safe for human consumption. The culturing of MTC is time consuming and inappropriate to be applied with fresh meat and food. Therefore, a rapid method "PMA qPCR" to differentiate living and dead cells of MTC was developed in this study. By treating with 50 μM PMA™ dye, dead M. bovis BCG (≤10 cells/ml meat suspension) could be completely discriminated and was not detected by specific MTC PCR. The limit of detection of MTC without treatment with PMA™ dye was 10 cells/ml. All 50 venison samples obtained for field study purposes were negative for MTC. However, 40% were slightly PCR positive for non-TBC mycobacteria. By culturing using selective enrichment, one single colony of M. avium was isolated. This is the first report on the isolation of M. avium from venison. Considering the difficulties of diagnosing mycobacteria in various matrices, the developed PMA qPCR is applicable for the differentiation of dead and living cells of MTC in meat samples.
引起动物源性牛型结核（bTB）的病原体是牛分枝杆菌和山羊分枝杆菌，它们属于结核分枝杆菌复合群（MTC）。感染 bTB 的野生红鹿通常没有病理发现，因此其肉可能被归类为可安全供人类食用。MTC 的培养是一个耗时的过程，不适合用于新鲜肉类和食品。因此，本研究开发了一种快速方法“PMA qPCR”来区分 MTC 的活细胞和死细胞。通过用 50µM PMA™染料处理，可完全区分 ≤10 个/ml 肉悬液中的死牛分枝杆菌 BCG，并用特异性 MTC PCR 检测不到。未经 PMA™染料处理的 MTC 的检测限为 10 个细胞/ml。为现场研究目的获得的 50 个鹿肉样本均未检出 MTC，但有 40%的样本对非结核分枝杆菌的 PCR 呈弱阳性。通过使用选择性富集进行培养，从鹿肉中分离到一株鸟分枝杆菌单菌落。这是首次从鹿肉中分离到鸟分枝杆菌的报告。鉴于各种基质中分枝杆菌诊断的困难，开发的 PMA qPCR 适用于肉样中 MTC 活细胞和死细胞的区分。
